1. Field of the Invention
This invention relates to an assembly robot by which parts can be assembled automatically at a high speed. This invention also relates to an improvement of the invention of Japanese patent application No. 21161/1979 (Assembly robot) filed Feb. 23, 1979.
2. Description of the Prior Art
Hitherto, a rectangular coordinated robot and a cylindrical coordinated robot have been well known as types of assembly robots. However, with these known robots, the working ranges are relatively small and the degrees of movement in each direction are the same. This leads to the fact that when these robots conduct an assembling operation, for instance to insert a peg into a hole, the peg cannot be controlled with regard to suitable position and attitude. Thus, these robots have the defect of causing jamming at the entrance of the hole.
In order to avoid such defect, Japanese application No. 21161/79 discloses an assembly robot having a selective movement or compliance, i.e., directionally different compliance, and having a multiple jointed arm construction provided with more than two shafts to give two dimensional locational coordinates to the assembly tool. A second link (second arm) is connected swingingly to the end of a first link (first arm), and swinging devices are connected to each of the first and second links. However, it has become evident that the swinging device connected to the second link becomes a weight load on the swinging device of the first link, and therefore that if the weight of the swinging device connected to the second link is heavy, the operational speed of the assembly robot will be reduced.